Untreated hypomagnesaemia can lead to tetany, recurrent seizures and status epilepticus as well as cardiac arrhythmias. Hereditary hypomagnesaemia with secondary hypocalcaemia (HSH) is a rare autosomal recessive disease of intestinal magnesium absorption caused by different transient receptor potential melastatin 6 (TRPM6) gene mutations. This condition typically presents in the neonatal period with neuromuscular excitability and refractory seizures.

Material and methods:

Here, we are reporting the clinical characteristics, follow-up and genetic analysis of two Turkish siblings with HSH both presented with recurrent a febrile convulsions starting in the first year of life.

Results:

Hypomagnesaemia, hypocalcaemia, low serum parathyroid hormone level and high urinary magnesium excretion were detected in both patients’ laboratory. Both had homozygous mutation of p.Lys1584Glu in the TRPM6 gene and parents were heterozygous for this mutation. Patients’ seizures were corrected by intravenous magnesium sulfate and calcium replacement. Calcium therapy was discontinued and the symptoms did not recur with oral magnesium therapy. Both had no clinical symptoms on follow-up (17 and 15 years) with normal growth and development with proper magnesium replacement.

Conclusions:

As early diagnosis and prompt magnesium replacement are essential to prevent long term squeal.